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Problem 6: {15 points) Epidemiologists have found a new communicable disease running rampant in College Station, Texas. They estimate that t days after the disease is first observed in the community, the percent of the population infected by the disease is approximated by (t) _ 20t3 - t4 p _ 1000 forO S t S 20. a) After how many days is the percent of the population infected a maximum? If necessary, round your answer to the nearest whole number. Include units in your answer. b) What is the maximum percent of the population infected? if necessary, round your answer to two decimal places. Include units in your